This invention relates to a method and apparatus for obtaining the individual responses of audience members to a question put to them, and in particular to such a method and apparatus including remote units operated by audience members to record a response and a central control unit to retrieve the responses stored in the remote response units. The invention finds application as an educational aid to determine the comprehension level of the pupils in a class, but may additionally be used commercially to conduct audience preference polls and the like.
A long-felt need that has eluded a practical solution is obtaining immediate feedback from audience members to a question put to them. In conducting a lecture, the lecturer may wish to occasionally pose a question to the class to monitor the comprehension level. If the class response indicates a high level of comprehension, then the lecturer may wish to proceed to new material. If comprehension is less than desirable, a review of the subject matter may be appropriate. In another setting, a marketing plan evaluation session may include presenting various options to a test audience and taking an immediate poll of the audience to determine their preferences for various packaging designs, logos, advertisements and the like.
Response systems are of two basic types: hard-wired, in which the remote units are interconnected with the central unit by conductors, and wireless. While the hard-wired systems provide more options for designing the circuitry in a manner to provide rapid collection of the responses, the conductors discourage anything but a permanent installation in a particular room and usually at a high installation cost. The wireless systems provide flexibility in allowing the system to be used in various settings and to be moved at will. However, the fact that wireless systems must communicate over broadcast signals tends to limit the options in system design. The result is that speed of response is compromised, making known wireless response systems unacceptably slow in accumulating the responses, especially if the system includes a large number of remote response units, such as 250.
In one known wireless response system, a central control unit transmits a signal simultaneously to all response units. Each response unit responds to the signal by returning a response after a predetermined time delay unique to the particular response unit. The central unit receives and records the responses. The problem with such a system is that sufficient dead space must be provided between response intervals to accommodate drift in the operation of the response units. In another known wireless remote system, the central unit transmits an address word to all response units and receives a reply from the response unit to which the particular address word is assigned. After the reply is received, the next address word is transmitted. Such units are also unacceptably slow because the central unit must wait to receive a response after transmitting an address word before transmitting the following address word. Additionally, the data transmission rate must be kept relatively slow because the central unit and the response units all operate from individual clock sources, which are subject to drift and require close tolerance components. Other difficulties experienced in such prior wireless systems include susceptibility to erroneous data and inherent complexity in the central unit software design if it is desired to test data word validity and to retry a unit whose response is not valid. Further, practical difficulties may arise in isolating problems that may occur in setting up a system, especially by a nontechnical person.